1da15a10d7
Add new instruction predicates to support the 'I' encoding recipe: IsSignedInt, IsUnsignedInt used to test that an immediate operand is in the allowed range.
69 lines
1.7 KiB
Python
69 lines
1.7 KiB
Python
"""
|
|
RISC-V Encoding recipes.
|
|
|
|
The encoding recipes defined here more or less correspond to the RISC-V native
|
|
instruction formats described in the reference:
|
|
|
|
The RISC-V Instruction Set Manual
|
|
Volume I: User-Level ISA
|
|
Version 2.1
|
|
"""
|
|
from __future__ import absolute_import
|
|
from cretonne import EncRecipe
|
|
from cretonne.formats import Binary, BinaryImm
|
|
from cretonne.predicates import IsSignedInt
|
|
|
|
# The low 7 bits of a RISC-V instruction is the base opcode. All 32-bit
|
|
# instructions have 11 as the two low bits, with bits 6:2 determining the base
|
|
# opcode.
|
|
#
|
|
# Encbits for the 32-bit recipes are opcode[6:2] | (funct3 << 5) | ...
|
|
# The functions below encode the encbits.
|
|
|
|
|
|
def LOAD(funct3):
|
|
assert funct3 <= 0b111
|
|
return 0b00000 | (funct3 << 5)
|
|
|
|
|
|
def STORE(funct3):
|
|
assert funct3 <= 0b111
|
|
return 0b01000 | (funct3 << 5)
|
|
|
|
|
|
def BRANCH(funct3):
|
|
assert funct3 <= 0b111
|
|
return 0b11000 | (funct3 << 5)
|
|
|
|
|
|
def OPIMM(funct3, funct7=0):
|
|
assert funct3 <= 0b111
|
|
return 0b00100 | (funct3 << 5) | (funct7 << 8)
|
|
|
|
|
|
def OPIMM32(funct3, funct7=0):
|
|
assert funct3 <= 0b111
|
|
return 0b00110 | (funct3 << 5) | (funct7 << 8)
|
|
|
|
|
|
def OP(funct3, funct7):
|
|
assert funct3 <= 0b111
|
|
assert funct7 <= 0b1111111
|
|
return 0b01100 | (funct3 << 5) | (funct7 << 8)
|
|
|
|
|
|
def OP32(funct3, funct7):
|
|
assert funct3 <= 0b111
|
|
assert funct7 <= 0b1111111
|
|
return 0b01110 | (funct3 << 5) | (funct7 << 8)
|
|
|
|
|
|
# R-type 32-bit instructions: These are mostly binary arithmetic instructions.
|
|
# The encbits are `opcode[6:2] | (funct3 << 5) | (funct7 << 8)
|
|
R = EncRecipe('R', Binary)
|
|
|
|
# R-type with an immediate shift amount instead of rs2.
|
|
Rshamt = EncRecipe('Rshamt', BinaryImm)
|
|
|
|
I = EncRecipe('I', BinaryImm, instp=IsSignedInt(BinaryImm.imm, 12))
|